Heat-sealing machine



H. POKRAS HEAT-SEALING MACHINE Feb. 4, 1958.

Filed Aug. 5. 1955 5 Sheets-S1- eet l IN V EN TOR.

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1953 H. POKRAS HEAT-SEALING MACHINE 3 Sheets-Sheet 3 Filed Aug. 5, 1955 x 5 f 5 N zm e 0V 0 pm. W a. W I z w y United States Patent H A -S ALING Harry Pokras, Los Angeles, Calif., assignor to Product Packaging. Engineering, Culver City, Calif., a corporation of California Application August 5,1955, Serial No. 526,747

2 Claims. (Cl. 154-42) This invention relates to heat-sealing machines, that is, to machines for heafisealing-the .marginsof heat-scalable material. Included in the objects ofthis invention are:

First, to provide a heat-sealing machine wherein .the width of the margin of material to .heheat-sealedrnay be readily and quickly adjusted.

Second, to provide amachine of this class wherein mere insertion of the material into the machine energizes an electric circuit which actuates a clamping piston and timing device so that the material is clamped and subjected to heat for a predetermined interval.

Third, to provide a machine of this class which incorporates a novel elongated piston bar.

With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings in which:

Figure 1 is a perspective view of the heat-sealing machine;

Fig. 2 is a rear view thereof, with the housing shown in section;

Fig. 3 is a fragmentary, longitudinal sectional view, taken through 3-3 of Fig. 4;

Fig. 4 is a transverse sectional view through 4-4 of Fig. 2, showing portions in elevation;

Fig. 5 is a fragmentary transverse sectional view through 5-5 of Fig. 3, showing particularly the piston block, piston and movable clamp jaw;

Fig. 6 is a fragmentary sectional view through 6-6 of Fig. 3, showing one end of the piston;

Fig. 7 is a perspective view of the piston; and

Fig. 8 is a wiring diagram, showing the electrical relationship of the various components of the heat-sealing machine.

The heat-sealing machine includes a base structure 1 having near its back portion upstanding bracket members 2 having horizontally extending upper portions under which is secured a piston block 3. The under side of the piston block is provided with an elongated piston cavity 4 which is in the form of a channel semicylindrical at its axial extremities.

The piston block 3 receives a piston bar 5 which is in the form of an elongated bar, rectangular in cross-section and semicylindrical at its axial ends so as to fit slidably into the piston cavity 4.

The piston bar 5 is provided with a peripheral groove which receives a yieldable seal ring 6. Secured to the under side of the piston bar 5 is a pressing head or movable clamp jaw 7, which extends axially beyond the piston bar and is provided with a pressing pad 8 formed of heatresistant material.

The axial extremities of the pressing head 7 are provided with upwardly directed stems 9 which pass through guide bores formed in the ends of the piston block 3. The upper extremities of the stems 9 receive springs 10 and nuts 11 which are adjusted so that the springs tend to retract the pressing head 7 upwardly and force the piston bar 5 upwardly into the piston cavity 4.

M u t below th upp r or movable lamp i 7 and in registry therewith is a heater block or fixed clamp jaw 12, The, heater block is formed of heat-conductive material and contains one or more heat elements 13. and a suitable conventional temperature regulatonnot shown.

The under side of the heaterblock 12 is reeessed, as indicated by 14, to provide a series of feet which rest on an insulating-pad 15 and is secured to the base structure 1 by bolts 16, which are preferably-isolated from the base structureby insulation washers 17.

Supported on the forward portion of the base structure 1, by means of supports or posts 18, is a table 19, the upper surface of which is flush with the upper surface of the heater block 12. One edge of the table 19 is provided with a removable edge guide 20.

At one end, of the piston block 3 there is provided a Pai of narall l horizontal bores which r ive guide bars 21 and 22. One of the guide barsprojects forwardly of the other and ,is-providedwith aknob 0r handle 23. A locks rewi leis; ented to e screw-threaded laterally in he endiqftthenis on blo k 3. as to enga 4 Of the guide bars, thereby to lock the guide relative to the piston block.

The guide bars 21 and 22 support a microswitch 25 located behind the piston block 3. The microswitch is provided with a depending operating leaf 26. Pivotally connected at one side of the microswitch is a control lever 27 which is substantially L-shaped to include a vertical portion 28 and a horizontal portion 29, terminating in an upwardly directed trigger arm 30.

The vertical portion 28 is provided with a cross bar 31 positioned for engagement by the operating leaf 26 of the microswitch 25.

The control lever 27 is located immediately adjacent one end of the fixed and movable clamp jaws 12 and 7 so that a sheet of material guided by the edge guide 20 may contact the trigger arm 30. By reason of the adjustment afforded by the guide bars 21 and 22, the trigger arm 30 may be moved in transverse relation to the clamp jaws and thus act to determine the eflective width of these jaws.

The microswitch 25 operates on momentary contact and closes a lock-in relay 32, which in turn actuates a timer or time delay switch 33 including a switch element 34 across the armature of the lock-in relay so that after a predetermined interval the relay 32 reopens. The relay also closes a circuit through a solenoid valve 35 which is connected by a fluid pressure line 36 to the piston block 3 and its cavity 4.

The solenoid valve 35 is supplied through a line 37 from the output or low pressure side of a pressure regulator 38. The pressure regulator is also connected by a branch line 39 to a pressure gauge 40. The intake or high pressure side of the regulator is connected through a fitting 41 to a source of air or fluid pressure, not shown.

The bracket members 2 and piston block 3 and other elements of the machine are encased in a housing 42 which is provided with a clearance slot 43 at the axial ends of the fixed clamp jaw 12. The housing includes a front panel 44 on which is mounted the timer 33, pressure regulator 38,

gauge 40, as well as manual switches 45 and 46 as may be desired, and indicator lights 47 and 43.

By reason of the provision of the elongated piston bar 5, pressure is uniformly distributed along the length of the movable clamp jaw 7, irrespective of the length of material it is desired to heat seal. By reason of the trigger arm 30, the width of the material subjected to the heatsealing operation may be adjusted. By moving the trigger arm 30 and guide bar 21 outwardly, the efiective width of the clamp jaws is reduced; conversely, by moving these members inwardly the effective width is increased.

While a particular embodiment of this invention has tented eb- 4, 195.

been shown and described, it is not intended to limit the same to the exact details of the construction set forth, and it embraces such changes, modifications, and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

I claim:

1. A heat-sealing machine, comprising: a heating block adapted to receive heat-scalable material on its upper surface; a cylinder block disposed above said heating block, having an elongated piston cavity therein; an elongated piston bar in said cavity; a yieldable seal means surrounding said piston; an elongated presser bar carried by said piston and cooperating with the upper surface of said heating block to press heat-scalable material therebetween; a table disposed outwardly from and substantially flush with its upper surface to support work pieces of material for insertion between said heating block and'presser bar; a trigger finger at one end of said heating block; means for adjusting the position of said trigger finger transversely of said heating block; and control means actuated by said trigger finger to supply pressure fluid to said piston bar for a predetermined interval.

2. A heat-sealing machine, comprising: a base structure having a pair of upstanding bracket members; a heated clamp block disposed on said base structure forwardly of said bracket members; a table forwardly of said clamp block having a work surface flush with the upper surface of said clamp block; an elongated piston block disposed above said clamp block and having an elongated piston cavity in its under side; an elongated piston bar having a peripheral sealing element fitting said cavity; an elongated movable clamp jaw carried by said piston and engageable with said heated clamp block to seal heat-scalable material inserted therebetween; a trigger finger at one end of said heated clamp block and engageable with the edge of the material inserted between said clamp block and jaws; means for adjusting the position of said trigger finger transversely of said clamp block to regulate the effective width thereof; and control means actuated by said trigger finger to supply pressure fluid to said piston bar for a predetermined interval, thereby to heat seal material disposed between said clamp block and jaw.

References Cited in the file of this patent UNITED STATES PATENTS 2,509,439 Langer May 30, 1950 2,574,094 Fener et al. Nov. 6, 1951 2,621,704 Langer Dec. 16, 1952 2,730,161 Langer Ian. 10, 1956 2,751,965 Miller June 26, 1956 

